WARNINGS
Included as part of the PRECAUTIONS section.
PRECAUTIONS
Hepatic Injury
Severe hepatic injury including cases of hepatic failure,
some of which have been due to autoimmune hepatitis, has been rarely reported
in patients taking EXTAVIA. In some cases, these events have occurred in the
presence of other drugs or comorbid medical conditions that have been
associated with hepatic injury. Consider the potential risk of EXTAVIA used in
combination with known hepatotoxic drugs or other products (e.g., alcohol)
prior to EXTAVIA administration, or when adding new agents to the regimen of
patients already on EXTAVIA. Monitor patients for signs and symptoms of hepatic
injury. Consider discontinuing EXTAVIA if serum transaminase levels
significantly increase, or if they are associated with clinical symptoms such
as jaundice.
Asymptomatic elevation of serum transaminases is common
in patients treated with EXTAVIA. In controlled clinical trials, elevations of
SGPT to greater than five times baseline value were reported in 12% of patients
receiving interferon beta-1b (compared to 4% on placebo), and increases of SGOT
to greater than five times baseline value were reported in 4% of patients
receiving interferon beta-1b (compared to 1% on placebo), leading to
dose-reduction or discontinuation of treatment in some patients [see ADVERSE
REACTIONS]. Monitor liver function tests [see Drug-induced Lupus Erythematosus].
Anaphylaxis And Other Allergic Reactions
Anaphylaxis has been reported as a rare complication of
interferon beta-1b use. Other allergic reactions have included dyspnea,
bronchospasm, tongue edema, skin rash, and urticaria [see ADVERSE REACTIONS].
Discontinue EXTAVIA if anaphylaxis occurs.
The removable rubber cap of the diluent (Sodium Chloride,
0.54% Solution) pre-filled syringe contains natural rubber latex, which may
cause allergic reactions and should not be handled by latex-sensitive
individuals. The safe use of EXTAVIA pre-filled syringe in latex-sensitive
individuals has not been studied.
Depression And Suicide
Depression and suicide have been reported to occur with
increased frequency in patients receiving interferon beta products, including
interferon beta-1b. Advise patients to report any symptom of depression and/or
suicidal ideation to their healthcare provider. If a patient develops
depression, discontinuation of EXTAVIA therapy should be considered.
In randomized controlled clinical trials, there were
three suicides and eight suicide attempts among the 1532 patients on interferon
beta-1b compared to one suicide and four suicide attempts among 965 patients on
placebo.
Congestive Heart Failure
Monitor patients with preexisting congestive heart
failure (CHF) for worsening of their cardiac condition during initiation of and
continued treatment with EXTAVIA. While beta interferons do not have any known
direct-acting cardiac toxicity, cases of CHF, cardiomyopathy, and
cardiomyopathy with CHF have been reported in patients without known
predisposition to these events, and without other known etiologies being
established. In some cases, these events have been temporally related to the
administration of interferon beta-1b. Recurrence upon rechallenge was observed
in some patients. Consider discontinuation of EXTAVIA if worsening of CHF
occurs with no other etiology.
Injection Site Necrosis And Reactions
Injection site necrosis (ISN) was reported in 4% of
interferon beta-1b-treated patients in controlled clinical trials (compared to
0% on placebo) [see ADVERSE REACTIONS]. Typically, ISN occurs within the
first four months of therapy, although postmarketing reports have been received
of ISN occurring over one year after initiation of therapy. The necrotic
lesions are typically 3 cm or less in diameter, but larger areas have been
reported. Generally the necrosis has extended only to subcutaneous fat, but has
extended to the fascia overlying muscle. In some lesions where biopsy results
are available, vasculitis has been reported. For some lesions, debridement,
and/or skin grafting have been required. In most cases healing was associated
with scarring.
Whether to discontinue therapy following a single site of
necrosis is dependent on the extent of necrosis. For patients who continue
therapy with EXTAVIA after injection site necrosis has occurred, avoid
administration of EXTAVIA into the affected area until it is fully healed. If
multiple lesions occur, discontinue therapy until healing occurs.
Periodically evaluate patient understanding and use of
aseptic self-injection techniques and procedures, particularly if injection
site necrosis has occurred.
In controlled clinical trials, injection site reactions
occurred in 78% of patients receiving interferon beta-1b with injection site
necrosis in 4%. Injection site inflammation (42%), injection site pain (16%),
injection site hypersensitivity (4%), injection site necrosis (4%), injection
site mass (2%), injection site edema (2%) and nonspecific reactions were
significantly associated with interferon beta-1b treatment. The incidence of
injection site reactions tended to decrease over time. Approximately 69% of
patients experienced injection site reactions during the first three months of
treatment, compared to approximately 40% at the end of the studies.
Leukopenia
In controlled clinical trials, leukopenia was reported in
18% of patients receiving interferon beta-1b (compared to 6% on placebo),
leading to a reduction of the dose of interferon beta-1b in some patients [see
ADVERSE REACTIONS]. Monitoring of complete blood and differential white
blood cell counts is recommended. Patients with myelosuppression may require
more intensive monitoring of complete blood cell counts, with differential and
platelet counts.
Thrombotic Microangiopathy
Cases of thrombotic microangiopathy (TMA), including
thrombotic thrombocytopenic purpura and hemolytic uremic syndrome, some fatal,
have been reported with interferon beta products, including EXTAVIA. Cases have
been reported several weeks to years after starting interferon beta products.
Discontinue EXTAVIA if clinical symptoms and laboratory findings consistent
with TMA occur, and manage as clinically indicated.
Flu-like Symptom Complex
In controlled clinical trials, the rate of flu-like
symptom complex for patients on interferon beta-1b was 57% [see ADVERSE
REACTIONS]. The incidence decreased over time, with 10% of patients
reporting flu-like symptom complex at the end of the studies. The median duration
of flu-like symptom complex in Study 1 was 7.5 days [see Clinical Studies].
Analgesics and/or antipyretics on treatment days may help ameliorate flu-like
symptoms associated with EXTAVIA use.
Seizures
Seizures have been temporally associated with the use of
beta interferons in clinical trials and postmarketing safety surveillance. It
is not known whether these events were related to a primary seizure disorder,
the effects of multiple sclerosis alone, the use of beta interferons, other
potential precipitants of seizures (e.g., fever), or to some combination of
these.
Drug-induced Lupus Erythematosus
Cases of drug-induced lupus erythematosus have been
reported with some interferon beta products, including EXTAVIA. Signs and
symptoms of drug-induced lupus reported in EXTAVIA-treated patients have
included rash, serositis, polyarthritis, nephritis, and Raynaud's phenomenon.
Cases have occurred with positive serologic testing (including positive anti-nuclear
and/or anti-double-stranded DNA antibody testing). If EXTAVIA-treated patients
develop new signs and symptoms characteristic of this syndrome, EXTAVIA therapy
should be stopped.
Monitoring For Laboratory Abnormalities
In addition to those laboratory tests normally required
for monitoring patients with multiple sclerosis, complete blood and
differential white blood cell counts, platelet counts and blood chemistries,
including liver function tests, are recommended at regular intervals (one,
three, and six months) following introduction of EXTAVIA therapy, and then
periodically thereafter in the absence of clinical symptoms.
Patient Counseling Information
Advise the patient to read the
FDA-approved patient labeling (Medication Guide and Instructions for Use).
Instruction On Self-Injection
Technique And Procedures
Provide appropriate instruction
for reconstitution of EXTAVIA and methods of self-injection, including careful
review of the EXTAVIA Medication Guide. Instruct patients in the use of aseptic
technique when administering EXTAVIA.
Tell patients not to re-use needles or syringes and instruct
patients on safe disposal procedures. Advise patients of the importance of
rotating areas of injection with each dose, to minimize the likelihood of
severe injection site reactions, including necrosis or localized infection [see
Medication Guide].
Hepatic Injury
Advise patients that severe hepatic injury, including
hepatic failure, has been reported during the use of EXTAVIA.
Inform patients of symptoms of hepatic dysfunction, and
instruct patients to report them immediately to their healthcare provider [see
WARNINGS AND PRECAUTIONS].
Anaphylaxis And Other Allergic Reactions
Advise patients of the symptoms of allergic reactions and
anaphylaxis, and instruct patients to seek immediate medical attention if these
symptoms occur. Inform latex-sensitive patients that the removable rubber cap
of the diluent pre-filled syringe contains natural rubber latex [see WARNINGS
AND PRECAUTIONS].
Depression And Suicide
Advise patients that depression and suicidal ideation
have been reported during the use of EXTAVIA. Inform patients of the symptoms
of depression or suicidal ideation, and instruct patients to report them
immediately to their healthcare provider [see WARNINGS AND PRECAUTIONS].
Congestive Heart Failure
Advise patients that worsening of preexisting congestive
heart failure have been reported in patients using EXTAVIA. Advise patients of
symptoms of worsening cardiac condition, and instruct patients to report them
immediately to their healthcare provider [see WARNINGS AND PRECAUTIONS].
Injection Site Necrosis And Reactions
Advise patients that injection site reactions occur in
most patients treated with EXTAVIA, and that injection site necrosis may occur
at one or multiple sites. Instruct patients to promptly report any break in the
skin, which may be associated with blue-black discoloration, swelling, or
drainage of fluid from the injection site, prior to continuing their EXTAVIA
therapy [see WARNINGS AND PRECAUTIONS].
Flu-like Symptom Complex
Inform patients that flu-like symptoms are common
following initiation of therapy with EXTAVIA, and that concurrent use of
analgesics and/or antipyretics on treatment days may help ameliorate flu-like
symptoms associated with EXTAVIA use [see WARNINGS AND PRECAUTIONS and DOSAGE
AND ADMINISTRATION].
Seizures
Instruct patients to report seizures immediately to their
healthcare provider [see WARNINGS AND PRECAUTIONS].
Drug Induced Lupus Erythematosus
Advise patients that drug-induced lupus erythematosus has
been reported during the use of EXTAVIA. Inform patients of the symptoms of
rash, redness of the skin on the face, joint pain, fever and weakness, and
instruct patients to report them immediately to their healthcare provider [see
WARNINGS AND PRECAUTIONS].
Pregnancy
Advise patients that EXTAVIA should not be used during
pregnancy unless the potential benefit justifies the potential risk to the
fetus [see Use in Special Population]. Therefore, inform patients that
if a pregnancy is considered, or does occur, the risks and benefits of
continuing EXTAVIA should be discussed with their healthcare provider.
Nonclinical Toxicology
Carcinogenesis, Mutagenesis,
Impairment Of Fertility
Carcinogenesis
Interferon beta-1b has not been
tested for its carcinogenic potential in animals.
Mutagenesis
Interferon beta-1b was not
genotoxic in the in vitro Ames bacterial test or the in vitro chromosomal
aberration assay in human peripheral blood lymphocytes. Interferon beta-1b
treatment of mouse BALBc-3T3 cells did not result in increased transformation
frequency in an in vitro model of tumor transformation.
Impairment Of Fertility
Administration of interferon
beta-1b (doses of up to 0.33 mg/kg/day) to normally cycling female rhesus
monkeys had no apparent adverse effects on either menstrual cycle duration or
associated hormonal profiles (progesterone and estradiol) when administered
over three consecutive menstrual cycles. The highest dose tested is approximately
30 times the recommended human dose of 0.25 mg on a body surface area (mg/m²)
basis. The potential for other effects on fertility or reproductive performance
was not evaluated.
Use In Specific Populations
Pregnancy
Pregnancy Category C: There are no adequate and well-controlled studies in
pregnant women; however, spontaneous abortions while on treatment were reported
in four patients participating in the interferon beta-1b RRMS clinical trial.
EXTAVIA should be used during pregnancy only if the potential benefit justifies
the potential risk to the fetus.
When interferon beta-1b (doses
ranging from 0.028 to 0.42 mg/kg/day) was administered to pregnant rhesus
monkeys throughout the period of organogenesis (gestation days 20 to 70), a
dose-related abortifacient effect was observed. The low-effect dose is
approximately 3 times the recommended human dose of 0.25 mg on a body surface
area (mg/m²) basis. A no-effect dose for embryo-fetal developmental toxicity
in rhesus monkeys was not established.
Nursing Mothers
It is not known whether
interferon beta-1b is excreted in human milk. Because many drugs are excreted
in human milk and because of the potential for serious adverse reactions in
nursing infants from interferon beta-1b, a decision should be made to either
discontinue nursing or discontinue the drug, taking into account the importance
of drug to the mother.
Pediatric Use
Safety and efficacy in
pediatric patients have not been established.
Geriatric Use
Clinical studies of interferon
beta-1b did not include sufficient numbers of patients aged 65 and over to
determine whether they respond differently than younger patients.